טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentBarham Nathanael
SubjectStatic and Dynamic Mechanical Properties of Ceramic Matrix
Nanocomposites for Potential Ballistic Armor
DepartmentDepartment of Mechanical Engineering
Supervisors Professor Daniel Rittel
Professor Wayne D. Kaplan
Full Thesis textFull thesis text - English Version


Abstract

The unique properties which ceramics possess give them great potential for use in many engineering applications.  However, their low tensile strength is their main disadvantage and is the major limitation in their ability to be used in many applications.  As a result, much research has been focused on trying to increase the tensile strength of ceramics.   Nanocomposites have been shown to possess higher tensile strengths potentially allowing them to be used for many applications where normal ceramics would fail.  This study has been done in conjunction with the Materials Engineering Department to test their nickel-alumina nanocomposite in order to determine its static and dynamic flexural strength, and provide an accurate characterization of the fracture micromechanisms.  Three batches of alumina and nickel alumina were made; one using the Pressure Filtration method and the other two using the Slip Casting method.  The test results of each batch were evaluated to understand how the fabrication methods influenced the strength of the material.  The tensile results proved yet again that flaws play an important role in a ceramic’s strength.  However, the results also showed that the nanoparticles do affect the flexural strength of nanocomposites and that the nanoparticles cause the alumina to have a strain rate sensitivity.  The results also show that the Pressure Filtration method produces superior results than the Slip Casting method.  The fractographic analysis showed that transgranular and innergranular fracture occurred in both the alumina and nickel alumina specimens, and that the strength of the material was connected to the amount of nanoparticle distributed in the material.